Study On The Synthesis And Biological Modification Of Pure Gold Nanocages

Gold nanocages have recently attracted extensive attentions in photothermal therapy,drug delivery and bio-imaging,due to their tunable surface plasmon resonance absorptions?SPR?and hollow structure.At present,metal replacement method is the best method to prepare gold nanocage,but there is a problem of cytotoxicity of residual silver and easy collapse of nanocage.In this paper,a new solution is proposed to improve the mechanical strength of the gold nanocage by hydrothermal treatment,and avoid the collapse of the gold nanocage,and then continue to etch the gold nanocage with HAuCl₄ to remove the silver from the gold nanocage.In addition,the gold nanocages were conjugated with antibodies and proteins to use targeted therapy in the biomedical field.The antibodies and proteins are expensive and difficult to be preserved.We synthesizing mercaptol folic acid,which also has targeting function used to modify gold nanocage so that it has biological targeting function and is used for drug loading and photothermal therapy.Firstly,the spherical silver nanoparticles were prepared with 40-60 nm to use as sacrifice template by chemical reduction method.The AuNCs were prepared by depositing gold atoms on the surface of silver template by replacement reaction.Then the gold nanocages were hydrothermal treatment at 150?.At high temperature,the loose arranged gold atoms in the gold shell transform loose state to tightly connected dense structure,thus improving the mechanical properties of the gold shell and avoiding the collapse of the final gold nanocage.After hydrothermal,the internal Ag template was completely etched with HAuCl₄ to obtain pure gold structure.In addition,sulfydryl was successfully introduced into folic acid to modify gold nanocages,due to antibodies and proteins are expensive and difficult to be preserved,that make it has the function of biological targeting and used for drug loading and photothermal therapy.The AuNCs was characterized by transmission,ultraviolet?UV?and XRD.The results showed that the structure of the gold shell was changed and the size of the cage was reduced by the same hydrothermal treatment,and the gold cage could not be dispersed to pieces in the end.The mercapto-folic acid and mercapto-gold nanocage were characterized by IR,Raman,DSC,fluorescence and transmission.The results showed that the sulfhydryl groups were introduced into folic acid and were successfully modified on the surface of gold.